The least flycatcher (Empidonax minimus) (also called chebec, or chebecker, after the sound it makes) is a small insect-eating bird.

[2][3] However, mitochondrial DNA analysis has revealed that the least flycatcher diverges significantly from its congeners and does not possess any sister taxa.

They often live in villages or city parks, nesting in shade trees and orchards, or along rural roads and forest edges.

[10] The vocalization of the least flycatcher is often characterized as being dry and sounding like a piercing «che-bec» pushed with strength, the second syllable being louder than the first.

[12] From there, he sings the Che-bec repeatedly and rapidly during the morning (about 60 times per minute), losing some speed and regularity throughout the day.

[9] Those perches are mainly dead twigs of the bottom part of a tree located in opened patches of the forest.

[11] In short, Robinson and Holmes (1982) determined that the least flycatcher attacks 81.1% of their preys by hovering, 9.6% by hawking, 6.2% by flush-chasing and 3.1% by gleaning.

[17] The courtship behavior of the least flycatcher remains largely unknown but it is thought to involve the male chasing the female through trees.

[13] Once pairs form, the female starts building their nest on either the forks of small trees like maples, birches, or ashes, or on the top of a large branch.

[11] The female builds the nest by weaving fine pieces of grass, strips of bark, twigs, lichen, spider and caterpillar webs, animal hairs and feathers, and other plant-derived materials together to form a tidy cup,[7][11] a process that takes her about five days.

[7][11] The female incubates the eggs for a period of 13 to 16 days while the male remains in the area and occasionally feeds her.

[7][12] If another least flycatcher intrudes their territory, the resident male quickly reacts, uttering a sharp note and adopting a threat-display.

[12] In its threat-display, the male attempts to look bigger by "fluffing out its breast feathers, raising its chest, extending, vibrating and bending the wings, spreading and flicking the tail up and down, and crouching".

[10] The least flycatcher leaves its wintering ground relatively early in comparison to other birds, arriving back north in late April to mid-May.

[10] The least flycatcher spends its breeding season in southern Yukon to central Quebec and Maritime Provinces, in Wyoming Indiana, New Jersey and in the mountains of North Carolina.

[7] The reason why the molt of the adults is delayed remains unclear, but might be due to the highly competitive site selection of winter habitat, where the first to arrive are the first to be served.